Update DiaBLa.py

DiaBLa.py

@@ -170,6 +170,8 @@ class Diabla(datasets.GeneratorBasedBuilder):
                         if info_to_remove in dialogue[user]:
                             del dialogue[user][info_to_remove]
                 dialogue_info = {k: dialogue[k] for k in dialogue_info_keys}
+                if dialogue_info['end_time'] == None:
+                    dialogue_info['end_time'] = ''
                 # Main data: the utterances
                 for utterance_id in dialogue['utterances']:
                     utterance = dialogue['utterances'][utterance_id]